The present invention relates to a physical layer circuit, a data transfer control device, and an electronic instrument.
In recent years, Universal Serial Bus (USB) has attracted attention as an interface standard for connecting electronic instruments. USB is widely used as an interface for connecting a personal computer as a host with a printer or an optical disk drive as a device (peripheral).
In recent years, it has been demanded that a portable telephone or the like be provided with a data transfer control device which implements USB. In the case of incorporating a USB data transfer control device into a portable telephone which operates using a battery, it is preferable to reduce power consumption of the data transfer control device to be incorporated. Various conventional technologies have been proposed as a technology for implementing a reduction of power consumption.
In USB, a data transfer operation is started after a USB cable is connected and the voltage of a VBUS line rises. Therefore, if electric power is consumed by a receiver circuit of the data transfer control device before the USB cable is connected, a problem occurs in which the battery power of the portable telephone is uselessly consumed.